1. Field of the Invention
The present invention relates to a continuously variable valve timing apparatus. More particularly, the present invention relates to an electric continuously variable valve timing apparatus of which entire length may be reduced and engine layout may be simplified.
2. Description of Related Art
Generally, a continuously variable valve timing apparatus (CVVT or Camshaft phaser) is a device which may adjust the timing of the opening and closing of valves.
A general continuously variable valve timing apparatus, usually used in vehicle makers, i.e. a vane-type variable valve timing apparatus, needs relatively small volume and is economical.
The vane-type variable valve timing apparatus, however, uses lubrication oil of an engine, and thus, when oil pressure is low, rapid and accurate control cannot be expected.
Particularly, in idle state, in high temperature, in start condition and so on, when engine oil pressure is not sufficient, relative phase change of a camshaft cannot be obtained, and excessive exhaust gas is generated.
While an electric variable valve timing apparatus may overcome the drawbacks, however for maintaining valve timing which is controlled, power consumption continues and entire length of the apparatus has to be lengthened.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.